Telephone system.



PATENTED MAR.- 29, 1904.

R. HAMILTON. TELEPHONE SYSTEM.

I0 'KODEL bell of his instrument.

which connects the calling and the calledsta- UNITED STAT-Es Patented March 29, 1904.

PATENT OFFICE.

ROBERT HAMILTON, OF MILTON, MASSACHUSETTS. i

TELEPHONE SYSTEM.

1 SPECIFICATION forming part of Letters Patent No. 755,868, dated March 29, 1904.

Applioationa'led February 7, l1903. Serial Na 142,286. (No model.)

To all when@ it may concern.-

Beit known that I,ROBERT HAMILTON, a citi- -zen of the United States, and a resident of Milton, in the county of Norfolk and State of Massachusetts, have invented new and useful Improvements in TelephoneSystems, of Which the following is a speciiication.

My invention relates to telephone systems, and particularly to that class commonly called ,par.ty-'linev systems, wherein a group of telephone instruments is includedV any one of which may be used to call up any of the others and when the call is responded to by the instrument at the station called the remainder of the instruments are excluded from using the system, `thus insuring privacy of conversation and non-interference with or interruption of the persons talking.A In the Patent No. 664,757, granted to U. S. Jackson December 25, 1900, a system of this class Ais shown and described, and in Patent No. 673,796, dated May 7, 1901, and granted to U. S. Jackson, is shown and described an instrument for use in systems of this class.

In operating telephone systems of the character described in No. 664,757 the operator at the calling-station is required to depress and to hold depressed for atime a push-button to call up another station. The depression of the push-button sets in motion a pointer which traverses a numbered dial, and when the pointer is oppositethe number of the station which it is desired to call it indicates that that station is connected with the calling-station. Thereupon the operator at the callingstation releases the push-button and rings the The same operation tions excludes all the other instruments on the line from the use of thesame and locks them in such a manner thatthey cannot break into the talking-circuit in use nor be operated at all. After completing conversation the system is again returned to `the normal condition by again depressing the push-button at the calling-station and holding it depressed until the pointer returns to its normal position at Zero, when all the other instruments on the systemwill beY unlocked and reset at zero and.

prepared for use in the manner above set forth. Reference is made to said Patent No. 664,757 for a more detailed description of this system. If, however, the operator at the calling-station neglects to depress the push-button after' using his telephone for the purpose of returning the system toits normalcondition,

the system remains inoperative so far as use by any other than the calling and the called stations is concerned, and the :other stations., continue to be excluded from use of the sys-- tern until the push-button at said calling-station is depressed a second time to return itsv engaging nger carried by a spring-actuated disk. Said disk is normally lockedy stationary by a movable bolt. Upon disengaging the bolt from the disk the latter is free to rotate until its finger engages the stop-pin, which indicates that the calling and called stations are connected. In order to return the system to its normal condition after use, the operator must remove the stop-pin, from the path of. the finger; otherwise the other instruments ofA f the system will be excluded from use thereof.y The primary object of my invention is to 'prevent the possibility of telephone systems of this character being rendered practically `inoperative in the manner above described and to provide a system Whichwill be automatically returned to its normal` condition when the receiver at thecalling-station is returned by the user toits hook or other f support. I am thus enabled to dispense with the necessity of a separate operation bythe user at the calling-station, the omission of which in the existing systems, either through Vinadvertence or design, entails such serious consequences. I n

My invention resides in the combination in a telephone system of a telephone-circuiua receiver, a movable holder for the receiver, means for controlling said circuit comprising a rotatable wheel, a stop-engaging member operated by a magnet as.

adjustably fixed to the wheel, a stop movable l into and out of the path of said member, and means controlled by the receiver-holder for operating the stop to disengage it from the stop-engaging member and free the wheel when the receiver is returned to its holder after use, so that the wheel will return to its normal position.

In the preferred form of my invention the stop is carried by the armature of a magnet arranged in a circuit in which is also arranged a switch adapted to be closed by the holder when the receiver is replaced thereon.

In the accompanying drawings, which illustrate one embodiment of my invention, Figure 1 is a diagrammatical view of a telephone system or' the character above referred to containing my invention, and Fig. 2 is a detail hereinafter described. Referring to the drawings, A. represents a telephone instrument located at one station, and A' a telephone instrument located at another station. Other stations and instruments may be included in the system, if desired; but two stations are suiiicient to explain'my invention.`

The instrument A is connected by a wire a with the ground at G and by a wire a' with one contact member of a normally open switch co2, the other contact member of said switch being connected by a wire t3 with a wire C common to all of the instruments of the system. The instrument A', as well as all of the other instruments of the system, is connected with the ground G and wire C in like manner and, like instrument A, is provided with a switch a2.

Adjacent to each switch a2 is arranged a disk a', fixed to an arbor on which is also iixed a ratchet-wheel a5, engaged by a pawl a", carried by an armature a'. The armature a' is One end of the coil of magnet a8 is connected by a wire a with one contact member of a normally closed switch am, and the other contact member ofI switch am is connected by a wire au with the wire C. The other end of the coil-magnet a is connected by a wire am with one contact member of the switch af of instrumentv A', and the other contact member of the switch am of instrument AI is connected by a wire a with one end of the coil of the magnet as of that instrument. The other end of the coilV of the magnet a8 of instrument A' is connected by a wire L12 with the switch al of the next instrument of the system in the same maniixed a pinion 712 driven by a Gear 723 loose on an arbor 724. Mounted on gear 713 is a pawl b5, engaged by a ratchet-wheel 7;", fixed to arbor v71". Power is applied to arbor 7 through a spring fixed at one end to said arbor and anchored at its other end to a fixed stud bx. Fixed to the arbor b is a lever 7;, by means of which said arbor and ratchet may be turned in one direction relatively to gear b3 and pawl 7)" to wind up spring 7;', and when moved in this direction and then released spring b' tends to return said lever b to its original position. The return movement of the spring transmitted through pawl 7)", arbor 5*, and gear 723 rotates wheel b in the direction indicated by the arrow. Thus it will be observed that if any wheel 7; be permitted to make a complete revolution the switch al will be opened and closed twelve times, once for each notch in wheel b, and that as all of the magnets as are in the same circuit with the switches al they will all be caused to operate their armatures a' twelve times and each disk a* will make a complete revolution. It will be observed also that if any wheel 7) be permitted to rotate to the extent of one notch only all of the magnets 0,8 will-operate their armatures a' once and all of the disks a* will be moved onetweltth of a revolution, or one step. Each disk t4 carries a laterally-projecting pin or stud al* for operating switch af, and the pin a of instrument A, which may be regarded as station No. 1 of the'system, is normally separated from its switch a2 one step, while the pin a of instrument A', which may be regarded as station No. 2 ot' the system, is normally separatedv from its switch t2 two steps. The pin a of the next instrument of the system (No. 3, not shown) is separated from its switch a2 three steps, and thus throughout the system. Therefore when the magnets as are caused to operate their arrr itures once only the pin a" of instrument A will be shifted into position to close its switch @awhile the pins alof the other instruments, which are normally distant from their respective switches a2 more than one step, are simply moved one step nearer their switches a2, but not far enough t0 close said switches. Thus an operator at any instrument may by controlling the movement of wheel b connect his instrument with any one of the other instruments of the system he may desire.

controlled, I provide each with a stop-engaging member c, herein shown as a pin adapted to be inserted in any one of the sockets c' provided in wheel b and numbered to correspond with the numbers of the diferent stations of the system. When an operator at any instrument desires to connect his instrument with any one of the other stations, he inserts the member c in the socket 0' corresponding in number ot' the station to be called and then depresses lever b. The re- IOO IIO

To r enable the movement of the wheels to bel lease of this lever causes 'wheel to be rotated, as already described, until member c engages stop c2, which is normally in the path of member c, and limits the extent of movement of wheel b, so that switch am is operated only that number of times which corresponds to the number of the station being called. The operation of the switch al() at the callingstation results in the operation of all of the disks a4, yet when wheel is stopped by stop c2 only the switch a2 at theA station being.

called and corresponding to the number of the socket occupied by c will be closedby the pin a of itsdisk In order that the switch a2 at the callingstation also will be closed to complete the telephone-circuit which isl made up through the wire C and the ground and the wires a, a', and as at the calling and called stations, I provide each instrument with a bell-crank lever d, one arm of which engages switch a2 and the other arm a stud d on lever 59. When lever b9 is thrown down by the operator at the calling-station to start wheel b in motion, stud d is carried out of engagement with lever CZ and the latter is swung by a spring Z2 in a direction to close its switch a2, so that the switch a2 at the calling-station is closed as well as the switch at the called station. When member c engages stop 02, the movement of lever 69 toward its normal position is arrested, thus preventing said lever from opening switch a2 while the system is in use. After having connected his instrument with the instrument he has selected the operator manipulates the ,usual bellhandle B and removes the receiver R from its hook r to place it to his ear. Each receiver holder or hook is pivoted at r and arranged to coperate with a spring contact member r2, fastened to the frame of the instrument. 'Ihe receiver-holder r is connected by a wire r3 with one end of the coil of a magnet r4, and the other end of the coil of magnet r4 is connected by a wire 75 with one pole of a battery r6, the other pole of which is connected by a wire r" with the spring member r2. The top side of the spring contact member r2 is covered with an insulating layer, so that when the receiver R is removed from the hook r and the inner end of the latter is forced by a spring rs down past contact member r2 and into a position below it the circuit through battery r6 and magnet r4 is not closed. The armature r of magnet r* carries the stop c2 and is pivoted at r1",

so that when operated by magnet r* the stop c2 is swung into and out of the path of the stopengaging member c.- When the operator at the calling-station replaces the receiver on its hook r, the inner end of the latter is carried up past the spring contact member r2 and in contacting with the under or conductor side of said member closes the circuit through battery r6 and magnet r4, and the armature r9 is moved under the influence of magnet r4 in a ner end-is carried away from finger 61, thus freeing wheel Z). When stop c2 is operatedA as above described, and wheel b is freed to complete its revolution, the return of said;`

wheel to its normal position carries the inner end of lever b9 into theL path of inger Z210 and also carries saidfinger against the end of said lever.

In order to prevent the operation of any other instrument while any two are connected, each instrument is provided with a bell-crank lever e, one arm of which rests normally against a finger e', provided on its respective disk c, and the other arm of lever e is in the form of a hook. When all of the disks are operated through the operation of the lever b of the instrument at the calling-station, all of the fingers e' move out of engagement with the levers e simultaneously and the latter are swung each by a spring e2 so as to carry the hooked arms under the studs CZ of all of the levers b9, thus locking all of the levers ZJ in normal position, except, of course, the lever b at the calling-station, which is then out of coperative relation with its lever e.

From the foregoing it will be clear that a separate operation other than hanging up the receiver is not required of the operator to return the system to normal condition after being used, but that the mere act of the operaprising a rotatable wheel; a stop-engagingmember adj ustably connected with the wheel; a movable stop normally occupying an operative position in the path of said member, and means controlled by the receiver-holder for operating the stop.

IOO

IIO

2. In a telephone system, a telephone-circuit; a receiver; a movable holder for the receiver; means for controlling said circuit comprising a rotatable wheel; a stop-engaging member ad justably connected with the wheel; a movable stop normally occupying an operative position in the path of said member; and means controlled by the receiver-holder for shifting the stop out of and then back into the path of said member when the receiver-holder is moved in one direction.

3. In a telephone system, a telephone-circuit; areeeiver; a movable holder for the receiver; means for controlling said circuit comprising a rotatable wheel; a stop-engaging member adjustably connected with the Wheel; a movable stop normally occupying an operative position in the path of said member; an armature by which said stop is carried, a magnet for operating the armature; a circuit in which said magnet is arranged, and a switch in said circuit controlled and operated by the receiver-holder- 4:. In a telephone system, a telephone-circuit; a receiver; a movable holder for the receiver; means for controlling said circuit comprising a rotatable wheel; a stop -engaging member adj ustably connected with the Wheel; a movable stop normally occupying an operative position in the path of said member; an armature by which said stop is carried; a magnet for operating the armature; a circuit in which said magnet is arranged, and a switch in said circuit adapted to be closed by the holder when the receiver is replaced thereon.

5. In a telephone system, a telephone-circuit; a receiver; a movable holder for the receiver; means for controlling said circuit comprising a rotatable Wheel; a stop-engaging member adjustably connected with the wheel; a movable stop normally occupying an opel'- ative position in the path of said member; an armature by which said stop is carried; a magnet for operating the armature; a circuit in which said magnet is arranged, and a switch in said circuit adapted to be momentarily closed by the holder when the latter is depressed by the Weight of the receiver.

Signed by me at Boston, Massachusetts, this 8d day of February, 1903.

ROBERT HAMILTON.- Witnesses:

ARTHUR F. RANDALL, ROBERT CUSHMAN. 

